The invention relates to drill chucks and has for its object to provide an improvement therein. In particular, the invention relates to an improvement in or modification of the invention claimed in my prior U.S. Pat. No. 3,810,642.
According to the invention, there is provided an improvement in or modification of the invention claimed in my prior U.S. Pat. No. 3,810,642, that is to say a drill chuck provided with a body part in which jaws are slidably mounted for converging movement in respective bores; a nut member rotatably mounted on the body part but axially located in a circumferential groove encircling said body part, said nut member having screwthreaded engagement with said jaws for advancing said jaws through a forward portion of the body part to grip a drill shank, and for retracting said jaws; a gear element with which the teeth of an extraneous chuck key may be engaged to tighten or slacken the jaws; and a cylindrical or generally cylindrical sleeve formed separately from but connected to said nut member and extending rearwardly of the body part to rotatably engage a cylindrical portion of the body part remote from the nut member, the improvement or modification residing in the fact that abutment means are provided, acting between the cylindrical sleeve and the portion of the body part with which it is rotatably engaged, for holding said sleeve in its required position in relation to the nut member. The abutment means may be constituted by a shoulder formed integrally on the portion of the body part with which the cylindrical sleeve is rotatably engaged and over which a part of the sleeve which forms a bearing surface between the sleeve and body part will have been pressed to take up its required position. The sleeve will preferably have been made as a pressing from metal plate and in this case a part of the sleeve which forms a bearing surface between the sleeve and body part will preferably be constituted by a flange portion extending concentrically within the cylindrical or generally cylindrical shape of the sleeve. In this case also, a free edge of the flange will preferably be provided with a slight outward flare to facilitate assembly of the chuck, that is to say to facilitate the pressing of the flange portion of the sleeve over the portion of the body part providing the shoulder. On the other hand, the abutment means may be constituted by a self-locking ring pressed onto the portion of the body part with which the cylindrical sleeve is rotatably engaged, to abut against the end of said sleeve, the self-locking ring having radially inwardly projecting resilient fingers arranged to bite into the surface of the portion of the body part referred to, and in this case the portion of the body part with which the cylindrical sleeve is rotatably engaged may be circumferentially grooved for the reception of the radially inner ends of the resilient fingers of the self-locking ring. In this case also, an end wall of the sleeve against which the self-locking ring abuts may be recessed to accommodate said ring. Alternatively, in a case in which the sleeve has been made as a pressing from metal plate, the abutment means may be constituted by a plurality of tabs formed integrally with said sleeve to form radially inwardly projecting resilient fingers engaging a circumferential groove formed in the portion of the body part with which the sleeve is rotatably engaged. A still further possibility is that the abutment means may be constituted by a resilient split ring entered into a groove in the body part after the chuck has been assembled normally.